Fuse-plug



G. B. THOMAS.

FUSE PLUG.

APPLICATION FILED MAR.23. 1920.

Patented July 19, 1921;

GEORGE E. THO/Y1 F15 I UNITED STATES PATENT OFFICE.

GEORGE B. THOMAS, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THE BRYANT ELECTRIC COMPANY, OF BRIDGEPOBT, CONNECTICUT, CORPORATION OF CONNECTICUT.

ruse-rims.

Specification of Letters Patent. Patented J uly 19, 1921.

Application filed March 23,1920. Serial No. 33,062.

[0 all whom it may concern.

Be it known that I, Gnonon B. THOMAS. a. citizen of the United States of America, residing at Bridgeport, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Fuse-Plugs, of which the following is a specification.

My invention relates tofuse plugs, and particularly to the electrical connectlon between the fuse and the center and shell contacts of the plug. The-object of my invention is to provide simple and efficient terminals for a fuse of the type shown in the Goodridge Patent No. 1,330,630, dated February 10, 1920.

In the accompanying drawin s Figure 1 is a side elevation 0 a fuse plug in which my invention is embodied in one form, the screw shell side contact of the plug and the plug cap being omitted;

Fig. 21s a vertical section on the line 22, Fig. 1, showing the screw shell and cap in position;

Fig. 3 is a plan of the plug with the cap removed;

Fig. 4 is a perspective of the fuse and the associated spring terminal;

Fig. 5 is a vertical section corresponding to Fig. 2 but showing a modified construction of the spring terminal;

Fig. 6 is a perspective of the fuse and spring terminal shown in Fig. 5;

Fig. 7 is a partial vertical section through a plug showing a further modification of the spring terminal and having associated therewith a fuse wire; and

Fig. 8 is a perspective of the spring terminal shown in Fig. 7, together with the fuse wlre.

In the construction illustrated in the Goodridge patent above referred to, the connection between the fuse and the center and shell contacts of the plug is effected by direct mechanical engagement, thus eliminating the use of solder. While the construction there shown is perfectly satisfactory from an electrical stand oint, it involves certain manufacturing di culties which are remedied by m resent invention.

Referrin to igs. 1 to 4, the present plug comprises t e usual insulating body 10, having a fuse chamber 11 from which opens the 11 12 formed between the barrier 13 and the upper portion of the fuse body. The usual cap 14 closes the chamber, the interior of which is visible throu h the mica insulating disks 15. The entering end of the plug body is externally threaded at 16 to receive the screw shell 17 side contact, which forms the side wall of the lower portion of the well 12. At the nose of the plug a center contact disk 18 is secured by means of a rivet 19, the large head 20 of which overlies the lower perforated end 21 of the fuse strip 22, and thus forms a closure. for the hole through which the rivet passes.

- The opposite end 23 of thefuse strip is carried over the barrier 13 and down toward the bottom of the well 12. To establish electrical connection between this end of the fuse strip and the screw shell 17, I provide a spring terminal 24 having a base 25 adapted normally extends outward beyond the area defined by the shell 17, so that when the latter is screwed on the threads 16 of the plug body the spring tongue 24 is compressed and thus establishes good electrical contact with the screw shell, while at the same time forcing the base 25 of the terminal into intimate contact with the end 23 of the fuse.

This construction has the merit of affording sufficient range of adaptability to compensate for all practical variations in the diameter of the plug body, or in the screw shell, incident to the manufacture of these parts.

In Figs. 5 and 6 I have shown a modified form of the spring terminal. In addition to the spring tongue 24, which is angled from one end of the base 25 of the terminal, I have provided a second spring tongue 28 at the opposite end of the base and having an offset flange 29 which corresponds in function to the lug 26 of the construction shown in Figs. 1 to 4. This modification facilitates the assembly of the parts, since, upon insertion of the terminal, the spring tongue 28 is compressed in the upper portion of the well between the barrier 13 and the body of the plug 10 and serves to retai the terminal in position until the screw shell 17 is adjusted in position. The operation of assembling the spring terminal and fuse inthe well 12 may therefore be carried out at one place in the shop without danger of disarrangement of the spring contact before the screw shell 17 is adjusted at another part of the shop.

In Figs. 7 and S I have shown still another modification of the spring terminal. this form the base 25 is of suflieient length to extend substantially the full depth of the well, so that when the bend which forms the spring tongue 24. is bottomed in the well, the opposite end of thebase is still slightly above the top of :the barrier 13, and in the assembled plug iscngaged by the cap 14, or the insulating mica disks 15. This construction enables the operator to force the spring terminal down into the well 12 from the top of the latter in the direction of the arrow X,

Fig. K. While facilitating the insertion of the terminal in this manner, the method is not desirable whereth'e neck 30 of the well is so narrow that the compression ofthe the subsequent engagement between the terminal and the screw shell.

Of course this construction is available if desired, whatever type of fuse is used. I have shown,'however, inthese figures a Wire fuse instead of a fuse strip, as in the other figures, and I have, moreover, indicated the wire 'as of sufficient length to be not only carried down to the bottom of the well, but also angledzup at 31 between the spring terminal 24: and the screwshell 17, so that the fuse end is pressed by the latter directly against the screw shell.

The direct electrical connection thus established between the fuse and the screw shell is practically desirable for fuses of higher capacity-say 30-ampere fuses.

lVhen using a wire fuse the center contact end thereofiscurled into an eye 32, through which the center contact rivet 19 passes. A notch 33 may be formed in the spring bend to accu 'ately locate the fuse wire end with relation to :the springs.

Various modified forms of terminals will readilyoccur to those dealing wit-lithe prob- ;fecting the electrical connection between said fuse and screw shell.

2. A fuse plug comprising an insulating 'body having a fuse chamber and a well opening therefrom to the exterior of the body, a screw shell side contact closing the exterior opening of said well, a fuse extending into said well and a spring arranged in said well and having an outwardly extendmg tongue adapted to effect electrical connectlon between said fuse and the screw shell. i

3. A fuse plug comprising an insulating body havlng a fuse chamber and a well opening therefrom to the exterior of the body, a screw shell side contact closing the exterior openmg of said well, a fuse extending into said well and spring means for effectlng the electrical connection between said fuse and screw shell, together with means for maintaining said spring in predetermined position in said well.

4. A fuse plug comprising an insulating body having a fuse chamber and a well opening therefrom to the exterior of the body, a screw shell side contact closing the exterior opening of said well, a fuse extending into said well and spring means for cfl'cct ing the electrical connection between said fuse and screw shell, together with spring means for-maintaining said terminals in predetermined position in the well.

5. A fuse plug comprising an insulating body having a fuse chamber and a well opening therefrom to the exterior of the body,'a screw slicll side contact forming aside wall of said well, a fuse extending into said well, and spring means for pressing said fuse against the screw shell to establish direct electrical contact between said parts.

In testimony whereof I have signed my name to this specification.

GEORGE B. THOB IAS. 

